Wetsanding

[Andy1972]

Anybody know the finer points of Wet sanding fiberglass in an effort to remove waterlines. I'm led to believe that I should use 2000 grit, followed up w/ compound, then wax to finish...., but any advice from experienced users would be greatly appreciated..


...and lastly, does this procedure leave the area in question at a greater risk of having watermarks anything else adhering to it in the future.

[skijones]

You have it. With 2000 grit paper, you will be rough polishing the surface. The compound will level out the scratches and finish with wax.

Seems kind of strange to dull a finish by sanding, but the end results are worth it.

[78LS2]

use 3M compounds. you can get them at napa, and they do a great job!

[DWhitt]

If it's just a waterline I would try Rubbing Compound followed by Polish and finally wax. 3M has a line specifically for gel coats. Works great. A high speed buffer is a must too.

[ClemsonDave]

I would start with the mildest abrasive and work my way up if it doesnt work. Try just the polish. If that doesnt work, try a swirl remover. If that doesnt work, try a rubbing compound. If that doesnt work, try 2k wet paper with soapy water. Once it comes out, work your way back to a polish. Then a polymer sealant or wax. Like DWhitt said, use a buffer, preferably a random orbit like the Porter Cable 7424 with Lake Country pads.

[James]

There may be no reason to go through all the effort of wet sanding/polishing and rubbing compound/waxing a hull waterline stain. The waterline stain is usually caused by chemicals/minerals in the water that penetrate into the porous gel coat. In most cases the stain can very quickly and very easily removed by appling Muriatic Acid with a damp cloth. Straight Muriatic Acid can be purchased at swimming pool supply stores (what I recommend and have used many times) and is available from most marine stores in the formulation of many diffent hull cleaning products. Muriatic Acid MUST be used in a WELL ventilated area or OUTDOORS. You MUST wear quality rubber gloves and eye protection. You MUST protect the trailer (If Muriatic Acid comes in contact with the trailer immediately rinse with H2O). Apply a 50% (dilute with H2O) to 100% solution, depending on the severity of the stain, with a damp cloth. Wipe down the hull in small areas as if you were waxing the hull. The acid generaly has no effect on decals and pin stripes but some care should be used the avoid them. If you use undiluted Muriatic Acid we may notice a white vapor coming off the hull and cloth. This is normal. Allow the acid to penetrate for a minute or so and then rinse with copious amounts of water with a clean rag or hose. A second application is rarely necessary but depends on the severity of the stain. Finally, wax the hull. You will be very impressed with the results. This prcedure or Acetic Acid (vinegar) may also be used the remove hardwater spots with excellent results. Good Luck.

[Mikeski]

Grant did a detailed write-up complete with pictures, hit the search key.